Blvra, short for biliverdin reductase A, is a pleiotropic enzyme. It converts biliverdin-IX-alpha into bilirubin-IX-alpha, an antioxidant and anti-nitrosative compound. This conversion is part of the heme degradation pathway. Bilirubin has various physiological functions such as antioxidant activity, immunosuppressive effects, and is recognized as a hormone with endocrine actions affecting cellular signaling pathways [1].

In Parkinson's disease (PD) research, a GK2-BLVRA fusion protein protected dopaminergic neuronal cells from oxidative stress in vitro and in vivo in a PD animal model. It reduced reactive oxygen species production, DNA damage, suppressed MAPK activation, and modulated apoptosis-related protein expression [2]. In hepatocellular carcinoma (HCC) and colorectal cancer (CRC), knockdown of Blvra in cell lines suppressed cell proliferation, invasion, and migration, and induced apoptosis. It was also found that Blvra exerted its effects via the Wnt/β-catenin pathway in both types of cancer [3,4]. In neonatal hyperbilirubinaemia, the G-allele at the rs699512 locus of the Blvra gene was associated with a decreased risk, suggesting that Blvra genetic variants are potential markers for predicting this disorder [5].

In conclusion, Blvra plays a crucial role in multiple biological processes, especially in antioxidant defense and cellular redox regulation. Its involvement in diseases like PD, HCC, CRC, and neonatal hyperbilirubinaemia has been revealed through functional studies. These findings from in vivo and in vitro models help understand the underlying mechanisms of these diseases and may provide new therapeutic targets.